Railway traffic controlling apparatus



4 SheetsSheet l r w fi/Ill L f QV XIIILF Qi m 9 K I w 0 N h w \SQ R Q @Q m m MRMM x U M. L W m w n mm. M U MW 2m J N B g $5 T1 L5 B n m w n .W K Nam J o? 6 T m m e B M m H N- v \Swkw mg Qww as @Q mam NwN May 13, 1947. .-H. s. YQUNG RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 4, 1945 May 13, 1947. H. s. YOUNG RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 4, 1943 4 Sheets-Sheet 2 Q If .ITI Y N m k3 V ITIMM mv M wwww mg m I Irll v n xl n mm in m a m 5 n M? Eng w MW m B T H msfi Swm A zx @QEL Rum 3 \NQQ Q Q L May 13, 1947. H. s. YOUNG RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 4, 1943 4 Sheets-Sheet 3 INVENTOR Henry J. Hum BY QZW HIS ATTORNEY SQ mt r \w May 13, 1947. H. s. YOUNG RAILWAY TRAFFIC CONTROLLING APPARATUS 4 Sheets-Sheet 4 Filed Sept. 4, 1943 mm A R l i m whi Patented May 13, 1947 RAILWAY TRAFFIC CONTROLLING APPARATUS Henry S. Young, Wilkinsburg, Pa... assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application Septembet l, 1943, Serial No. 501,254

My invention relates to railway trafiic controlling apparatus and more partcularly to a centralized traffic control system for governing train movements over a single track railway, and is an improvement upon the'system disclosed in my Letters Patent of the United States N 0. 2,326,991, issued August 17, 1943, for Railway traiiic controlling apparatus.

My invention contemplates the provision of an absolute permissive block system comprising automatic signals for both directions at spaced points in each single track stretch with opposing headblock signals at each end for governin traffic movements into the stretch, all. controlled over a reversible line circuit system employing but two line wires, together with other headblock signals for governing .trafilc movements into the passing tracks, the latter being controlled over separate line circuits for the two directions. The control of the signals in accordance with traffic conditions is eiiected by the provision of continuous track circuits for all main track, having track relays the contacts of which control the line circuits.

My invention also contemplates the provision of a communication system of the impulse code type, having a coding unit at each of a plurality of field stations located at the ends of the passing sidings for controlling the operation of the track switches from a distant point such as a train dispatchers ofllce, and for superimposing manual control upon the headblock signals and for governing the direction of trafiic, the code system also serving to indicate the condition of the switches and signals and the movement of trains at the control office.

One object of my invention is the provision of an improved arrangement of electrically interlocked circuits at the control ofiice governed by the control levers for those signals which govern train movements into the single track stretch, so as to prevent interference with train movements in the event of improper manipulation of these levers and to prevent the reversal of the direction of traffic except when the single track stretch is unoccupied.

Another object of my invention is the provision of an improved system of directional control in the field, involving the control of the reversible line circuit system for the signals for the single track stretch by directional stick relays at the opposite ends of the stretch, which relays are operated by control codes sent to both ends of the stretch to set up the desired traific direc- 13 Claims.

tion under the control of a master directional relay at the oflice.

Another feature of my invention relates to the control of a block indicator at the oifice to indicate when any portion of the single track stretch is occupied, which'indicator is controlled jointly by codes transmitted from both ends of the single track block under the control of relays governed over the reversible line circuit system by which the signals are controlled, no additional line wires being needed.

Another object of my invention resides in the provision of improved arrangements for electrically looking all hand throw switches giving access to the main track in the territory covered by the system, including time controlled means for enabling the switch to be unlocked to permit a train to enter the side track, together with means subject to control by the central office operator for governing movements out of the side track, the remote control of the electric switch locks being attained by controlling the signal line circuits in a suitable manner.

Other objects, purposes and features of my invention will be pointed out as the description proceeds.

I shall describe one form of apparatus embodying my invention and shall then point out the novel features thereof in claims.

Referring to the accompanying drawings, Fig. 1 shows a portion of a suitable machine located at the control office and arranged for the control of one form of apparatus embodying my invention, including control panels for two field stations located at the opposite ends of a single track block as indicated by the miniature track diagram at the top of the view, while Figs. 2A, 2B and 20 show a plan of the corresponding stretch of railway track together with the trackway apparatus and circuits. More particularly, Figs. 2A and 20 show the apparatus at two field stations including circuits for the control of a power op erated track switch and the opposing headblock signals which govern traffic movements into the adjoining single track and double track stretches. Fig. 20 also shows, at the right, the apparatus and circuits as provided for the control of an electrio lock for a hand throw switch located in the main track of the double track portion of the system comprising the passing siding, while Fig.

3 switch located in one of the single track sections.

It is to be understood that the system of my invention is made up of a number of unit portions each generally similar to the one shown in the drawings, and that the drawings are so arranged that the circuits extending to the righthand margin of Fig. 20 match those extendin from the left-hand margin of Fig. 2A, so that Figs. 20 and 2A, arranged end to end with Fig. 2A at the right, illustrate the track plan together with the apparatus and circuits for governing train movements through a passing siding, while Figs. 2A, 2B and 20, when arranged end to end in that order illustrate the trackplan for a single track block together with the apparatusand circuits for governing train movements from one passing siding to the next one. v

Similar reference characters refer to similar parts in each of the several views.

The code system employed for communication between the ofiice and stations is to be understood to be of the type shown in Letters Patent of the United States No. 2,229,249, issued January 21, 194i, to Lloyd V. Lewis, for Remote control systems but modified in two particulars to correspondwith theshowi'n gof the earlier Lewis patent', l lo. 2,197,130, issued AprillB, '1940, tl1ese modificationscomprising first, the provision of two additional steps in each control code, for the control respectively of a traffic direction controlling stick relay such as the relay 2RFS or and of another sticl; relaysuch as the relay 2WL$ o'rflWLfd for the control of an electric switch lock, and second, the provision of arrangement to enable these relays as well as the usual switch control relays lws and awe, and the usual signal control relays QLHS, ZRHS, ZLI-IS and l'tRl-ls to be of the stick polar type, as shown, all of these relays being of the stay-where-put t e arranged to be held in their last operated p' itions when d'eenergized. v V

, Any suitable remote co ntrol system other than the ones mentioned may also be used, a suitable system being shown, for example, in the pendin application for Letters Patent of the United States, Serial No. 496,907, 'filed July 3-1, 1 943, by Arthur P. J ackel, for Remote control systems.

Consideration of thedetailed mode 'o'f operation of the code communication system is not needed for anunder'standing of my invention and it is deemed sufficient to point out that codin units are provided at the since and at each stawhich are connected by line wires Y*Z', as indicated diagrammatically in the drawings,over which contro-l codes are transmitted at times from the elite to a selected station, while at other tinies indicationcode's aretransmitte'cl over the same line wiresir'om the 'difl'r'ent stations to the ofiice without interference. Each codeincl'ude's a distinctive code call by means of which a selector'relay such as the relay MS or 12S "at the off ce, and asimilar relay iS or 2S atone station only is energize to efiect the temporary establishlnent of a group of seven communication channels between the selected control panel at the o'ifice and the corresponding station to posit'ion a group of'stick relays. The different stations have different code calls, consequently the selector relays for different stations or panels are not energized at the same time, th'esame channels providing -communication at diflerent times with all the stations. The channels employed in the transmission of a control code from the o'ffice toa selected station are represented herein by a group of Wires i "to i, inclusive, while those eniployed in the transmission of an indication code from a station to the corresponding office panel are represented by another group of wires 9 to [5. inclusive.

Considering the station of Fig. 2A, for example, it is to be understood that the coding unit at that station includes a starting relay, not shown, which responds to a change in position of any of the indicating relays which provide connections from terminal B of the local source of current to the wires 9 to IE, as shown, and thereby eifects the delivery of an indication code to the line YZ during which a selector relay IS at the sending station and a delivery relay OI D at the offi'ce are temporarily energized in response to a distinctive code can to position a group of seven indication relays K in accordance with the condition of energization of the channels 9 to 15. The office indication relays governed from the station of Fig. 2A, for example, includes a track indication relay iTK controlling an OS lamp I'I'KEin the track diagram of Fig. 1 to indicate the condition of the track section IT containing the power operated track switch l W-Qrelay l'IjK being governed by a repeating relay ITP of the track relay I'IR for the section; normalfand Verse switch indication relays INWK and IRWK controllin the lamps INE and |RE assoclated with the control lever ISW for switch 'IW; and governed by the switchrepcating relays lNWP and IRWP which indicate the position "of switch 1W, provided such position corresponds 'With'that of its comm relay IWS and operating relay IWR; two signal indication relays 2LHK and zRHK controlling the lamps 2LE, 2NE and ZRE associated with the control lever ZSIG for the signals IRA, '2RB, ZLA and 2LB, and governed by relays ZLGP and 2RGP which repeat the stop indications of these signals; and two a proach indication relays 2LBK and ZRBK controlling the lamps ZLBE and BKE to indicate block occupancy. Relays ZL'BK and ZRBK are controlled by block repeating relays 2LBP and ZRBP which in turn are controlled jointly by line relays ZLHD and ZRI-ID which also control the entering headblock signals and by approach relays ZRAR and 2LAR in a novel manner as hereinafter described.

, Those relays which control the channels 9 to [5 at the station of Fig. 2C function-similarly to govern the indication relays K for the righthand panel in Fig.,1, in response to indication codes including a different cod call to which relays 3S and 03D are responsive, but in this case channel I4 is not used. It is to be understood that lamp GLBE is controlled by a relay similar to ZLBK but associated with the next control panel to the right of those shown. k The blool; indication lamp BKE is governed by codes transmitted from both stations by re- Iays Z-RBP and 4LB P one of which indicates the conditionof a portion of the single track block and the other that of theremainder.

The switch lever [SW and the signal lever 2 S I G of the left-hand panel of Fig. 1 are the usualswitchand signal levers for the code control of the switch stick relay I WS and the signal stick relays 2LHS and ZRI-IS at the station shown in Fig. 2A, while the levers 38W and 4SIG of thg-right-hand panel control similar relays 3W5, dill-IS and ERHS at the other field station, shown in Fig. 2C. The two signal IeVersZSIG and QS IG are electrical 1y interlocked with-respectto the control of train movements into the intervening single track stretch by the provision of a master difect'ional stick relay 2' lIlE as in in prior Patent No. 2,326,991, by means of which the desired trafiic direction, designated-by the operator by reversing one signal lever or the other, is selected automatically under the proper traflic conditions, as reflected by the block indication relays. Preferably the signal levers as well as the switch levers I SW and SSW are of the types mentioned in the Lewis Patent No. 2,229,- 249 and function generally as therein described. The push buttons lSTBand SSTB are the starting buttons for operating the usual code starting relays [ST and 3ST by means of which control codes are initiated and the corresponding stations selected. For example, when the button ISTB is operated, the closing of its contact a completes a circuit from the positive or supply terminal B of a suitable local source. of current or common return terminal C of the same source, and relay IST picks up to establish a stick circuit extending to terminal B at the back contact i of a selector relay 01S, associated with the same panel. Relay IST when energized initiates a control code as described in Patent No, 2,229,- 249, including a code call for energizing relay OIS of the same panel.- Relay OIS releases relay IST and connects terminal B to selected ones of the wires I to l in accordance with the positions of the control levers, and at the selected station, Fig. 2A a delivery relay ID responds to the code call to effect the operation of the selected stick relays; Relay IWS, for example, is

- through the winding of relay IST to the negative operated to normal or reverse over channel I or a 3 to correspond with the position of lever ISW. The other stick relays are each operated to normal or reverse in accordance with the condition of energization of a single control channel, a series of intermediate register relays F being interposed as in Patent No. 2,197,130, in order that this may be accomplished. Relay ZLHS or 2RHS is operated to reverse when lever ZSIG occupies its left-hand or right-hand position so as sition of the directionalstick relay 2- iLP above referred to.

As shown, the trackway circuits of Figs. 2A, 2B and 2C are set up for westbound traffic, that is to say, for train movements from right to left, as indicated by the lighting of the direction indicator lamp WFE offiFig. 1, with the left-hand contacts of relay 2-4LP closed, as shown. Accordingly, relay ZRFS is operated to the left by a code delivered by relay ID when relay IF"? is energized over channel 2, while relay GLFS is operated to the left by a code delivered by relay 3D when relay 3F2 is not energized.

It is to be noted that the contacts of relays 2--4LP, ZRFS and ALF'S all point to the left for westbound trafiic movements and to the right for eastbound traffic movements, that is to say, toward the exit end of the block, and that relays ZRFS and 4LFS are therefore operated in opposite directions in response to the energization of channel 2 to designate the exit end.

Since relays ZRFS and iLFS are located at diiferent stations, it will be evident that when the clearing of a signal involves the reversal of the direction of traflic, it requires the transmis- 6 sion of control codes to the, stations at both ends of the single track block. The initiation of the two codes is accomplished automatically, however, by a single operation of but one of the two starting buttons ISTB or 3STB in accordance with a feature of my invention, with the aid of a pair of slow release stick relays EFK and WFK controlled by relay 2-4LP. Thes two relays are controlled over circuits corresponding to those for the similarly designated relays shown in an application for Letters Patent of the United States, Serial No. 412,279, filed September 25, 1941, by James J. Van Horn, for Railway traffic controlling apparatus, now Patent No. 2,344,333, granted March 14, 1944. In additionto controlling the code transmission these relays also serve as direction locking relays.

contacts 0 bridge the contacts e of the block indication relays in the circuit for relay 2-4LP, so that relay Z-ALP is free to be operated to either position. This is desirable because it permits the operator to restore the original trafiic direction if, due to a fault, the desired reversal cannot be effected.

Assuming, for example, that a block clear indication has been received following the establishment of the right to left direction, as shown, relay WFK is picked up over a circuit extending from terminal B at the left-hand contact d of relay 2-4LP, back contact I) of relay EFK, front contacts 0 of relays .ZRBK and iLBK through the winding of relay WFK to terminal C, and is then held energized over a stick circuit including its own front contact a extending directly to terminal B at contact (1 of relay 24LP. If relay 2-4LP is now operated to the right to reverse the trafilc direction, the opening of its left-hand contacts I) and 01 causes the release of relays ZRBK, 4LBK and WFK, the latter relay being slow to release and consequently holding its back contact d open for a time suflicient to insure the release of relays ZRBK and 4LBK. Relay WFK remains released along with relay EFK until new block clear indications arereceived from both stations. If button ISTB is now operated, the closing of its contact or causes relay IST to pick up to initiate a control code for opcrating -rela ZRFSto the right, and relay 3ST will be operated over contact b of button ISTB and back contacts 9 of relays EFK and WFK to initiate a control codefor operating relay iLFS to the right. The same result may be attained by operating button BST'B, as will be clear from the drawing.

Levers ZSL and ASL are three-position levers for electric switch lock control and govern the polar stick relays ZWLS and 4WLS over channel '4. Lever 28L normally occupies its normal center position as shown, and is operated to the left or right to set up the corresponding traffic direction for a movement from a side track to the main line over a hand throw switch located in the single track stretch, such as the It is to be under-. stood that normally, the position of relay 2-llLP- is unoccupied. Lever ZSL is preferably of the push-turn type, such as is shown in Letters Patent of the United States No. 2,289,736, granted July 14, 1942, to Clarence S. Snavely and'Reg-is H. Zetwo, for Circuit controllers. It is to be understood that lever ZSL is restrained against rotation from one position to another by a detent which is released when the lever is pressed to close auxiliary contacts a and I). These contacts when closed complete the circuits for relays [ST and 3ST, and it follows that each operation of the rotary contacts c, d and e of lever ZSL from one position to another results in the delivery of codes to the stations at thetwo ends of the block within which switch 2W is located.

Lever 48L, associated with the right-hand panel, is of the same type as lever 28L, and the momentary closing of its contact a in response to the rotation of its contact from one position to another serves to initiate the transmission of a control code to operate relay AWL'S of Fig. 20 over channel 4, to govern the movement of a train from a side track to the main track of the adjacent passing siding over an electrically locked hand throw switch located in the block governed by signal 4RA or 2LA, such as the switch 4W in the right-hand portion of Fig. 2C.

Circuits for governing the control code channel 6 are not shown, as this is used for purposes having no bearing on my invention, such as for the control of a maintainers call signal, for example.

The directional relay .2-4LP is controlled generally in the same manner as in my prior Patent No. 2,326,991 except for'the auxiliary circuit provided by relays WFK and EFK, and for such modifications as are brought about by the addition of lever ZSL. That is to say, relay 2--4LP may be operated to the position shown by moving lever 4SIG or ZSL to the left, or to the reverse position by moving lever ZSIG or ZSL to the right, provided the indication relays indicate that the block is clear and that the headblock signals governing traffic movements into the block are at stop, as shown. The circuits for relay 2-'4LP extend from terminal B at back contact b of relay 3TK, back contact (1 of relay lLl-IK, front contacts e of relays 4LBK and ERBK, back contacts d and b respectively, of relays ZRHK and ITK, normal contacts e and d of lever 'ZSL to contacts b of levers ZSIG and iSiG. By moving lever llSIG or 23L to the left, the circuit is extended from contact I) of lever lSiG or the left-hand contact d of lever 23L over the center or left-hand contact a of lever ZSIG through the lower winding of relay Z lLP to terminal C, to operate the relay to the left, asshown. With lever 4SiG normal, or to the right, the movement of lever 281G or 28L 'to the right extends the-circuit from contact b of lever 2SIG or from the right-hand contact e of lever 23L over the center or right-hand contact a of lever 4SIG through the upper winding of relay '2-BLP to terminal C, to reverse the relay.

In response to a change in position of relay 2--4LP, relays 2RBK and A'LBK release, but the circuits for relay 2-4LP are maintained available so that the relay may be restored to its original position if desired by the provision of a branch connection including the back contacts 0 of relays EFK and WK, asalready explained.

Considering now the trackway apparatus of Figs. 2A, 2B and 20, it is to be understood that each of the signals is of thewell-known searchlight type and has a three-position mechanism such as that shown in Reissued Letters Patent of the United States of E. J. Blake No. 14,940, dated August 31, 1920, each such mechanism bein identified by the general reference character G prefixed by the designation of the corresponding signal shown symbolically in the track plan in the upper portion of these views. Each main line signal mechanism such as 4LAG or 2 IG controls a repeating relay such as lLAPC or ZIPC. Each signal repeating relay is energized when the signal indicates caution or proceed as indicated by the closing of the corresponding front contactY or G of its mechanism, except when the length of the block section in advance of the signal is less than that required to stop a high speed train. In the latter case, as illustrated by signals 2LA and 4RA, the signal repeating relay is energized only when the signal indicates proceed. Each signal repeating relay serves when energized to supply current of normal polarity to the line circuit for the next signal in the rear governing traffic in the same direction, to cause such signal to indicate proceed, as illustrated, for example, by signal 23 as shown. Each automatic signal, as shown in Fig. 2B, is provided with the usual directional stick relay such as ZISR which picks up when a train passes the signal at caution or proceed, which serves when energized to supply current of reverse polarity to the next signal inthe rear for the control of a following train. The headblock signals of Figs. 2A and 2C are normally lighted by suitable lamps, not shown, while the automatic signals are normally dark and lighted only upon the approach of a train, by the release of an approach relay such as the relay '2 IAR, which relay jointly with relay 22PC for the opposing signal 22, controls lamp 2 IE for signal'Z I, as shown.

Time looking for preventing the operation of the track switches IW and 3W except under proper trafiic conditions, and for electrically interlocking the opposing headblock signals which govern trafiic movements into the same block, is obtained by the provision of approach locking stick relays such as the relays ARAS and 4LAS controlled jointly by indicating relays such as the relay dRGP for signals ARA and lRB and relay ALGP for signals dLA and 4LB, and by the corresponding signal control relays 4RHS and ALI-IS. The arrangement is such that the clearing of the signal RA, for example, is made dependent upon the release of the approach locking relay lRAS which it controls, the latter relay having a back contact c in the circuit for mechanism 4RAG for signal ARA. In response to the reversal of thesignal control relay RRHS, a block repeating or route relay 4BPR becomes energized, provided traffic conditions at the time are such as to make it proper for the signal ARA to be cleared, that is, provided the route governed by signal EA is available. With relay ARHS reversed, the opening of back contact I) of relay GBPR causes relay (IRAS to release, and the closing of the front contact 17 of relay ABPR and of the back contact 0 of relay 4RAS then completes the circuit for energizing mechanism 4RAG.

Each approach/locking relay is reenergized automatically in the usual manner in response to the release of the track relay for the section directly in advance of the associated signal, and

also when a signal is manually put to stop, by the operation of a time element relay such as the relay 3TER controlled by relay dASP. Relay 4ASP also provides a distinctive indication at the office of the operation of relay 3TER. When relay dASP is picked up it initiates an indication code in which channels l3 and [5 are both connected to terminal B over its contacts b and 0, thereby energizing the office indication relays lLHK and 4RHK to extinguish lamp 4NE without lighting either lamp 4LE or 4RE. The indication lamps associated with the signal lever therefore remain dark until relay 3TER completes its operation to pick up the associated approach locking relay, whereupon relay 4ASP is released to transmit an indication code to again light lamp ANE.

Each of the track switches such as 3W governing movements into or out of the passing siding is operated by a switch machine such as 3SM controlled by a polar neutral switch operating relay 3WR in the normal manner, each such relay being controlled by the associated code controlled relay such as 3W8 over a circuit including front contacts of the approach locking relays such as ARAS and QLAS, and of the detector track relay 3TH,

Front contacts of the last named relays are also included in the connection to terminal C in the circuits for relay 3W5, rendering relay 3WS non-responsive to a control code except 1 under conditions which permit operation of the track switch. The circuits for the signal control relayssuch as 4LHS and IRHS have a back contact 0 of the associated time element relay 3TER included in the connection to terminal C, the provision of this contact serving to prevent the release of the approach locking relay 4RAS or 4LAS and its subsequent reenergization by relay 3TER unless relay 3TER starts its operation from its normal position so as to consume a predetermined time in closing its front contacts.

Considering now the hand throw switches 2W and 4W, it is to be understood that each such switch is provided with a suitable hand throw switch stand, such for example, as is shown in Letters Patent of the United States No. 2,184,870, issued December 26, 1939, to Herbert L. Bone and Kenneth J. J. McGowan, and that its operation is governed electrically by the provision of an electric switch lock controlled by a lock magnet such as 2WL, the electric switch lock being preferably of the type shown in Letters Patent of the United States No, 1,126,834, issued February 2, 1915, to Walter P. Neubert and William E. Smith. For an understanding of the present invention it is believed that it will suffice to point out that the operating lever 8 of the switch stand is normally locked mechanically in a position to maintain the track switch locked normal by a lever latch attached to a segment 25 which is held in lockingposition by the bail 50 of a padlock as indicated diagrammatically in Fig. 2B of the accompanying drawings and as shown in detail in Fig. 1 of the Neubert et al. patent. To unlock the switch, the padlock must first be removed by the train crew to permit the segment 25 to be moved a short distance to a position to engage the locking dog 21 and to close contacts 46-41, and to also open contact 49 to release an indicating relay such as ZWLP, Then if trafiic conditions as reflected by the circuits are such as to indicate that it is proper to unlock the switch, the lock magnet 2WL will become energized to open contact 48 and to lift the locking dog 27,

permitting segment 25 to be moved to its full reverse position in which the switch operating lever 8 is free to be operated, the segmentbeing held reversed mechanically as explained in the Neubert et a1. patent until leve 8 is again re-' stored to normal. It is also to be understood that the switch stand is equipped with the usual switch circuit controller and point detector having a contact N which is closed only when the switch is locked normal.

For movements into the side track, no cooperation with the central oifice operator is required, a circuit for energizing the lock magnet 2WL being prepared by the operation of a time element relay 2TER which is set into operation when a train enters the track section 22T in which the switch 2W is located. For movements out of the side track, the energization of two line relays WAR and EAR is required in order to obtain an unlock, these relays being controlled over the signal line circuit in response to the movement of the lever 2SL to the left or right as hereinafter described.

The mechanism and circuits for controlling switch 4W are generally similar to those for switch 2W as above described, except that the lock magnet 4WL is controlled over the signal line circuits from a, source of current at the station of Fig. 2C, movements into the side track being governed by the operation of a time element relay dTER, and movements out of the side track bya locking relay lWLSR controlled by lever 4SL. 4

The circuits for the control of electric switch looks as shown herein are an improvement upon those disclosed in an application for Letters Patent of the United States Serial No. 462,354, filed October 17,1942, by Harvey 1A. Haines, for Railway trafiic controlling apparatus, now Patent No. 2,367,723, issued January 23, 1945.

Considering now the reversible line circuit system for the single track stretch, the circuits as shown are set up for westbound trafiic, but with the head block signals at stop. The first section of the line circuit system corresponds with the block section extending from its exit end to signal 2| and provides a circuit for controlling that signal which may be traced from terminal B at the station of Fig, 2A through the winding of relay ZLAR, back contact b of relay 2LAPC, front contact I of relay ZRAS; normal polar contact b of relay 2RFS, front contacts I) of the track relays ITR and ZRTR for sections IT and 2RT, line wire 29, front contact b of the track relay -2ITR for section 2|T, back contacts b of relays 22PC and 22SR through mechanism 2IG and thence over contact 0 of relay 22SR, contacts a of relays 22PC and ZITR, line wire 28, contacts a of relays ZRIR, ITR and ZRFS, contact e of relay ZRAS and contact a of relay 2LAPC to terminal C of the same source. Mechanism 2IG is therefore energized in the reverse direction so that signal 2| indicates caution as shown, and relay 2LAR is also energized, indicating that the corresponding block section is clear, and completing a circuit from terminal B over the left-hand contact (2 of relay ZWLS and front contact a of relay 2LAR through relay fiRBP to terminal C. Since relay ZRBP is energized, it may be assumed that a code has been transmitted from the station of Fig. 2A to pick up relay ZRBK of Fig, 1, which relay as shown is held energized over a stick circuit extending from terminal B at the left-hand contact 72 of relay 2-4LP, back contact (1 of relay EFK, front con- 1 1 tact a of relay ZRBK, back contact I of relay 0] D throu h the windingoi relay 2RBK to terminal C.

In Fig. 2B, relay .2IPC is energized over .front contact Y of mechanism ZIG to complete the second section of the line circuit system corresponding to the block section extending from signal 2!. to signal 23 and providing a circuit for controlling signal 23, which extends from terminal 13 of the source at the location of signals 2| and 22 over the back contacts of mechanism 22B, relay ZIAR, front contact 0 of relay ZITR, front contacts a of relays 2IPC and 22TR, line wire 3E), front contacts a andb of relay ZWLP, line wire 32, front contact a of relay ZBTR, back contacts a of relays PC and 246R, through mechanism 23G, thence over contacts b of relays ZlSR, MPC and 2'3TR, line wire 33, contacts d and c of relay ,ZWLP, line wire 31, and contacts b of relays 22TR and ZIPC to terminal C. Mechanism 23G is energized in the normal direction to cause signal 23 to indicate proceed, and relay ZIAR, is also energized, becoming released to light lamp ZIE in response to the release of the track relay 2.3T or 22T by a train approaching signal 2|.

Relay ZEPC is energized .over the front contact G of mechanism 23G to complete the third section of the line circuit system corresponding to the block section extending from signal 23 to signal 4LA and providing a circuit for relay GLHD which may be traced from terminal B of the source at the location of signals 23 and 24 over the back contacts of mechanism 24G, relay 23AR,

contact 0 of relay 23TH, contacts a of relays 23PC and 24TH, line wire 34, front contacts a of relays ALTR, and 3TB, the normal polar contact a of relay ALFS, the winding of relay 4LHD and thence over contacts b of relays lLFS, 3TH, and ALTR, line wire 35, and contacts I) of relays ZQTR and 23PC to terminal C.

Relay 23AR. is therefore energized becoming released to light lamp 28E in response to the release of the track relay 3TB, lLTR or 24TH by a train approaching signal 23, and relay ALHD is energized in the normal direction, completing a circuit over its front contact a and normal polar contact 11 to energize relay 4LBP. It may be assumed therefore that a code has been transmitted from the station of Fig. 20 to pick up relay QLBK of Fig. l, which relay as shown is held energized over a stick circuit similar to that for relay ZRBK as above traced, the block indication lamp BKE being extinguished when relays ZRBK and ALBK are both energized as shown.

It will be seen that when the line circuit system is set up for westbound traffic as shown, the energization of relay ZRBK indicates that the block section extending from signal ZRA to signal 2| is clear. and that the energization of relay ALBK indicates that the two block sections extending from signal 2| to signal 23, and from signal 23 to signal 4LA, respectively, are both clear, consequently these relays when both energized indicate that the entire block from signal ERA to ALA is clear.,

I shall now assume that the operator desires to clear signal @LA to admit a westbound train to the single track block, with the apparatus initially in the condition shown in the drawings. The operator will move lever 4816 to its lefthand position and press button SSTB, thereby ener izing relay 381 to initiate the transmission of a control code tothe station of Fig. 20 in which channel 5 is energized over the left-hand contacts (I of relay 24LP and of lever lSIG, operating relay iLHS to reverse.

lhe approach locking relay GLAS associated with signal ZLA is normally held energized over a stick circuit extending from terminal B at the left-hand contact a of relay ALI-IS, front contact b of relay ZLGP and the front contact a and winding of relay ALAS to terminal C.

When relay lLI-IS reverses, the energization of this circuit is shifted to its right-hand contact a to include back contact a of the block repeating relay lBPR, but since relay GLHD is energized, relay iBPR now picks up over the circuit extending from terminal B at the left-hand contact b of relay RHS over contacts I) of relays iLI-IS and QLHZD, contacts a of relays SRWP and 3NWP, contact (1 of relay 3TP through relay ABPR. to terminal C. Relay iBPR opens its back contact a to release relay LAS, thereby completing a circuit for mechanism lLAG extending from terminal B at the right-hand contact a of relay 4LI-IS over front contact a of relay GBPR, front contact 0 of relay 4RAS, back contact 0 of relay lLAS, contact f of relay iLHD, front contact 0 of relay 3NWP, mechanism ALAG, back contact 0 of relay 3RWP, contacts e and c of relay iLHD, and contacts 0 of relays 4LHS and GRHS to terminal C, mechanism 4LAG being thereby energized in the normal direction to cause signal GLA to indicate proceed, and also energizing relay lLAPC, and releasing relay 'iLGP. The release of relay 4LGP initiates the transmission of an indication code to energize the office indication relay lLI-IK, thereby extinguishing lamp ANE and lighting lamp ALE. The opening of back contact d of relay ALHK opens the circuit for relay 2-4LP and the opening of back contact ie of relay ALHK renders lever 28L incapable of controlling relays GLFS and ZWLS, thereby maintaining the Westbound traffic direction.

Assuming next that the train passes signal 4LA at clear, the release of the track relay 3TB releases relays 3T1, ALI-ID and 23AR, lighting lamp 2313 to cause the signal 23 in advance to indicate proceed. Relay 3TB also closes a circuit momentarily at its back contact ,f to restore relay LHS to normal. Relays 4LBP and lBPR, mechanism lLAG, and relay 4LAPC also release, relay iLGP becoming reenergized to complete a pickup circuit for relay ALAS at back contact e of relay STR so that relay 4LAS becomes reenergized. An indication code is now transmitted to energize the ofiice indication relays 3NWK and 3TK and to release relays 4LBK and lLHK, consequently lamps ZTKE, BKE and 4NE become lighted and lamp lLE is extinguished.

When the train passes signal 23 at clear, the closing of back contact 11 of relay 23TR completes a pick-up circuit for relay 238R, which, when section MT is vacated, supplies current of reverse polarity to the line wires 34 and 35 over its contacts b and c, energizing relay ALI-1D in the reverse direction and thereby conditioning signal lLA to indicate caution in response to the reversal of relay 4LI-IS by another control code.

In the event the operator desires to clear signal ALB instead of signal 4LA, he Will reverse lever 33W, move lever ASIG to the left and then press button SSTB, transmitting a code to reverse relays 3W8 and GLl-IS. The circuit for relay QNWP includes a normal polar contact a of relay 3W8 and relay 3NWP releases quickly in response to the reversal of relay 3WS,.ancl prevents relay EBPR from picking up, consequently relay 4LAS remains energized and relay 3WR becomes energized in the reverse direction to operate switch 3W to reverse. Relay SRWP picks up when the switch becomes locked in its reverse position and by closing its front contact a completes the circuit for relay ABPR which then picks up to release relay dRAS.

With relay lLHS reversed and relays 4BPR and 3RWP energized, the closing of back contact of relay ALAS completes the circuit for mechanism 4RBG over front contact 0 of relay 3RWP to clear signal ALB.

I shall next assume that the apparatus has been restored to the condition shown and that the operator desires to reverse the direction of traflic and to clear signal ZRA to admit an eastbound train to the single track block. The operator will move lever 2SIG to its right-hand position, completing a circuit at the lever contact b to reverse relay 24LP, which releases relays 2RB-K, 4LBK and WFK as already described, and thereby extinguishes lamp WFE and lights lamps EFE and BKE, and he will then press button IS'I'B momentarily resulting in the energization of both of the starting relays IST and 3ST to send two successive control codes, one to each station. In the code sent to the station of Fig. 2A, channel 2 is deenergized and channels I and I are energized, causing relays 2RFS and ZRI-IS to reverse while in the code sent to the station of Fig. 2C, channel I and 2 are energized and relay 4LFS reverses. It may be that the operator also moves lever 451G to the right to clear the leaving signal iRA by the same code, as is permissible.

The reversal of relay ZRFS disconnects the adjacent current source from the reversible line circuit system and connects relay ZRHD thereto, causing the deenergization of the tandem connected line circuits governing westbound tra-nic thereby releasing relays ZLAR and. 2RBP, mechanism ZIG, relays MPG and ZIAR; mechanism 23G, and relays 23PC, 23AR, 4LHD and ALBP. The reversal of relay 4LFS disconnects relay GLHD from the line circuit system and connects terminals B and C of the source at the station of Fig. 2C thereto through the winding of relay ARAB, to initiate the energization of the tandem connected line circuits governing eastbound tranic, thereby causing relays iBAR, @LIBP, mechanism 24G, relays MPO and 24AR, mechanism 22G, and relays 22PC, ZZAR, 2RHD and TZRBP to become energized over circuits for governing eastbound traflic similar to the circuits for governing westbound traffic already traced. Signal ZRA then clears as the result of operations similar to those involved in the clearing of signal iLA as already described. More particularly, when relay ZRI-ID picks up it completes the circuit for relay ZBPR at its front contact b, since relay ZRHS stands reversed, and relay ZBPR picks up, opening its back contact b to release relay ERAS to complete a circuit for energizing mechanism ZRAG in the normal direction to cause signal ZRA to indicate proceed, and to energize relay 2RAPC and to release relay 2RGP.

When relay iLBP picks up, an indication code will be transmitted from the station of Fig. 2C to energize the office indication relay 4LBK. An

I indication code will also be transmitted from the ZLBP by the relays ZLHD and 2RAR in such a manner that the condition of the intermediate block section which extends from signal 22 to signal 23 is indicated by relay 4LBP when westbound traiiic is set up and by relay 2RBP when eastbound traffic is set up. That is to say, the indicating relay at the entering end indicates the condition of two of the three block sections and the one at the leaving end indicates the condition of the third block section.

After the eastbound traffic direction has been set up as described, the operator may restore signal ZRA manually to stop by transmitting the proper control code and may then reverse the trafiic direction to clear signal ALA by operations similar to those required when Westbound trafiic is already set up. However, if signal 2RA, for example, is put manually to stop, the reenergization of relay ERAS is delayed for a suitable time interval to protect against an improper change in traffic conditions in advance of a train approaching at high speed.

Assuming that mechanism ZRAG is energized, with section l'l unoccupied, relays ZRGP and ZRAS will be in the released position, and if relay ZRHS is restored to normal by the operator, mechanism ERAG releases and relay 2RGP picks .up. Relay ZASP becomes energized over the circuit extending from terminal B at contact a of relay ZRHS, contact I) of rela ZRGP, back contact a of relay ERAS, contact 6 of relay ITP, relay ZASP, and the left-hand contacts 0 of relays ZRHS and ZLHS to terminal 0. Relay lTE-R is energized over contact a of relay ZASP. The closing of contacts I) and c of relay 2ASP initiates an indication code, energizing channels I3 and 5 to pick up relays ZLHK and ERHK to extinguish lamp 2RE, but Without lighting lamp ZNE or ZLE. After a predetermined time interval relay ITER closes its front contacts a and b, contact a completing the circuit for relay ZRAS which picks up, releasing relay 2ASP to initiate a second indication code to release relays ZLHK and 2RI-IK and light lamp ZNE again.

I shall next assume that a westbound train passes from the single track block to section 2LT, and that the operator desires to clear signal 2RB for an eastbound train standing on the side track at the left of section IT. The operator will move lever ZSIG to the right as for clearing signal ERA as above described but in addition will reverse lever ISW before pressing button ISTB. In this case in the code sent to the station of Fig. 2A channels 3 and l are energized and channel 2 deenergized so that relays I WS, ZRFS and ZRHS reverse and a code is also sent to the station of Fig. 2G to reverse relay 4LFS, the operation of relays ERFS and ALPS reversing the line circuit system to set it up for eastbound trafiic as already described. The reversal of relay IWS releases relay INWP, preventing relay 2BPR from picking up, the circuit for relay ZBPR being open also at front contact I) of relay ZRH'D until the reversal of the line circuit system is consummated, and relay ERAS remains picked up, relay IWR becoming energized in the reverse direction to operate switch IW to reverse. Relay IRWP picks up when the switch becomes locked in its reverse position, relay ZBPR becoming energized to release relay ZRAS to effect the energization of mechanism ERBG for clearing signal ZRB in response to the energization of relays lRW'P and ZRHD, in this instance.

It will be clear that the reversal of trafiic direction is effected automatically, that is to say,

15 without special manipulation by the operator, the operations involved in setting up eastbound traffic and clearing signal ZRA or 2R3 being similar to those involved in clearing signal 41A or lLB when westbound trafiic is already set up.

It may be that the operator will desire to reverse the traific direction without clearing the entering signal for the new direction. To set up eastbound trafiic, for example, without clearing signal ZRA or ZRB, all that is necessary is to move lever ZSIG to the right to reverse relay 2-4LP, and to then restore it to its normal center position before pressing button ISTB, as will be readily apparent.

Considering now the line circuit system which extends'the length of the passing track, and placing Fig. 2A at the right of Fig, 20, it will be seen that relay ZLHD is energized, with its polar contacts reversed, over a circuit extending from ter minal B, Fig. 20, at front contact a of relay ERTR, over back contact b of relay lLAPC, contact 1 of relay ARAS, contact I) of relay BTP, back contact f of relay 4WLSR, front contact I) of relay ATEP, line wire 31, contact b of relay AWLP, line wire 4|, contact I) of relay 2LTR, relay ZLI-ID, contact a of relay ZLTR, line wire 40, contact a of relay 4WLP, line wire 36, contact a of relay A'I'EP, contact e of relay GWLSR, contact a of relay 3TP, contact e of relay lRAS, contact a of relay 4LAPC, and contact b of relay ARTR to terminal C, contacts a and b of relay ST? and contacts e and f of relay GRAS in the circuit as traced being bridged by contacts 6 and f of relay 3RWP when switch 3W is reversed.

Relay 4RHD i energized, with its polar contacts reversed, in series with relay ERAR over a circuit extending from terminal B, Fig. 2A, through the winding of relay ZRAR, back contact b of relay 2RAPC, contact J" of relay ZLAS, contact I) of relay ITP, contact (2 of relay ZLTR, line wire 43, contact d of relay 4WLP, line wire 39, back contact d of relay GVVLSR, back contact of relay 3TER,-contacts d of relays tTEP and ERTR, the winding of relay lRI-ID, contacts 0 of relays RT-R and GTEP, contact I) of relay QTER, contact 0 of relay 4WLSR, line wire 33, front contact c of relay QWLP, line wire 42, contact 0 of relay ZLTR, contact a of relay ITP, contact e of relay ZLAS, and back contact a of relay 2RAPC to terminal C, contacts a and b of relay ITP and contacts 6 and J of relay ZLAS in the circult as traced being bridged by contacts e and ,f of relay IRWP when switch IW is reversed.

It will be seen that the energization of relay ZLHD indicates that sections ART and 2LT are unoccupied, and that section 3T is unoccupied or switch 3 is reversed, while the energization of relays lRl-ID and ZRAR indicates that sections ART and 2LT are unoccupied, and that section IT is unoccupied or switch I is reversed. Consequently, the energization of relay ZLBP, as controlled by relays ZRAR and ZLHD, indicates that sections lRT and 2LT are unoccupied, as required for the control of the ofiice indication relay ZLBK governed by relay ZLBP, relay 2LBK controlling lamp ZLBE 0f the track diagram.

I shall now assume that the operator desires to clear signal 2LA to admit a westbound train to the block which extends to signal ERA when switch 3W is normal, and to the next signal in advance for the same direction, namely, to signal @LA when switch 3W is reversed. The operator will move lever ZSIG to its left-hand position and press button ISTB, thereby energizing relay IST to initiate the transmission of a con- 16 trol code to the station of Fig. 2A to operate relay 2LHS to reverse.

Vfhen relay ZLHS reverses, the stick circuit for relay ZLAS is shifted from the left-hand to the right-hand contact a of relay ZLHS, and if section IT is vacant and the line relay ZLHD is energized in the reverse direction, as shown, relay 2BPR becomes energized over the circuit in cluding contacts b of relays 2RHS, ELI-IS and ZLHD, back contact a of relay IRWP, front contact a of relay INWP, contact d of relay I'I'P through relay ZBPR to terminal C. By opening its back contact a, relay ZBPR releases relay ZLAS, which completes a circuit for mechanism ZLAG extending from terminal B at the righthand contact a of relay 2LHS, front contact a of relay 2BPR, contacts 0 of relays ZRAS and ZLAS, contact b of relay INWP, contact J of relay ZLI-ID, mechanism ZLAG, contacts e and c of relay ELI-ID, and the right-hand contact 0 of relay ZLHS to terminal 0. Mechanism ZLAG'is therefore energized reverse to cause signal 2LA to indicate caution, releasing relay ZLGP. If, now, signal QLA is cleared so as to energize relay GLAPC, relay ZLHD will become energized in the normal direction and will shift its polar contacts to cause signal ZLA to indicate proceed, energizing relay ZLAPC to reverse the polarity of the current supplied to the next signal 2| in the rear, causing signal 2| to indicate proceed. It is assumed that the distance from signal ZLA to signal GLA is less than that required to stop a high speed train, and consequently signal 2| is arranged to indicate proceed only if signal ZLA also indicates proceed.

I shall next assume that the operator desires to clear signal ELB to admit a westbound train to the upper passing track. The operator will reverse lever ISW, move lever ZSIG to its lefthand position and then press button IS'IB, to initiate a code for operating relays IWS and 2LHS to reverse. Relay ZBPR. is prevented from picking up by the release of relay lNWP by relay IWS as in the prior examples, and when switch lW becomes locked reverse in response to the reversal of relay IWS, relay iRWP picks up. If section IT is unoccupied, relay ZBPR then becomes energized over the circuit including front contacts a and g of relay IRWP and front contact d of relay ITP, and releases relay ZLAS to complete a circuit at its back contact 0 over contact I) of relay IRWP to operate mechanism ZLBG to reverse to cause signal ZLB to indicate caution.

Signals QRA and 4R3 may be controlled in a similar manner by the operation of levers 38W and 481G, as will be readily apparent from the drawings.

Considerin now the operation of the hand throw switch 2W, by reference to Fig. 23 it will be seen that when a train enters the track section ZZT containing the switch 2W, the dropping of the track relay 22TH, completes a circuit over the line wires 6d and 5 extending from the location of the track relay at signal 22 to the location of switch 2W, to initiate the operation of a time element relay ZTER. The line circuits for signals ZRA and lLA include front contacts a, b, c and d of a switch repeating relay EWLP which is normaily energized over a local circuit extending from terminal B over contacts 38 and 59 of the electric switch look, back contact 19 of relay ZTER and contact N controlled by switch 2W through relay ZWLP to terminal C, which circuit is broken by relay-'2TER when it starts its oper- 2 ,420, are

. r 17 i ation and serves to check that relay ZTER starts its operation from its normal position to measure a predetermined time before closing its front contact a, which time is of the order of several minutes and serves to prevent the unlocking of the switch in advance of an approaching high speed train. The crew of a train which consumes this time in section 22'1 and stops at switch 2W may unlock the switch by removing padlock 50 and closing contacts 4t-41 to pick up the lock -magnet EWL over the circuit having a connection to terminal 13 at contact a of relay ETER. Signals 22, 23, ZRA, QRB, MA and 41B are held at stop, their line circuits being held open by relay 22TH, until the train clears the main line, and by relay 2W LP until switch 2W is again locked normal.

To enable a train to enter the main line via switch 2W, the central oiiice operator in response to a telephone call from the train crew will move lever 25L to the left or right according to the direction the train is to move after entering the single track stretch, provided the entire block is unoccupied, and the entering signals are at stop. This results in the energization of relay 2- lLP over the left-hand contact d or the righthand contact e of lever 23L to operate relay 2-- iLP to a position corresponding to that of lever ESL, and the momentary closing of contacts a and b of lever ESL initiates two control codes, one to the station of Fig. 2A in which channel 4 is energized over the connection to terminal 13 including the lever contacts c and back contacts e of relays ZRHK and ALI-1K and contact h of relay OIS, to reverse relay ZWLS, and the other to the station of Fig. 20 in which channel 2 is energized irrespective of the position of relay 24LP, over contact h of relay 03S, to reverse relay 4LFS, The eastbound traffic direction will be set up in the portion of the line circuit system at the right of switch 2W by the reversal of relay lLFS and the westboruidtrafiic direction in the portion to the left of switch 2W, due to the closing of the right-hand contacts a and b of relay ZWLS, as will be apparent from the drawings and the opening of contact of relay EWLS will deenergize relay 'ZRBP to effect the delivery of an indication code to release relay ZRBK and thereby light lamp BKE.

Under these conditions the release of relay EWLP by the train crew results in the energizetion of relays WAR and EAR, provided there spective block portions extending to signals ZRA and ALA are unoccupied, with the left-hand portion of the line circuit system set up for West bound trafiic and the right-hand for eastbound traiiic, permitting magnet ZWL to be energized to unlock the switch over the connection to terminal B including the front contacts a of relays WAR and EAR. 1

After the unlock has been obtained, the central office operator will restore lever ZSL to its normal center position, closing the lever contacts a and b momentarily, resulting in the delivery of control codes to restore relay ZWLS to normal and to operate relays ZRFS and l-LFS to a position to correspondcwith that of relay 2-4LP as indicated by lamp WFE or EFE. If the train is westbound, for example, signal 2| will indicate caution or clear and relay 2 l SR. will become energized to cause signal 23 to indicate caution when the train vacatcs section 22'1, permitting signal iLA to be cleared for a following train providing switch 2W has been locked normal to energize relay 2WLP.

It will be apparent that other hand throw switches equipped like switch 2W may be located in any of the single track sections for operation in the manner described and that only one lever ESL is required regardless of their number or location within the single track block.

It will also be clear that the purpose of using a three-position lever such as 25L for switch control is to provide means for positioning relay 25SL to correspond with the desired direction of traffic movements in the single track block following the restoration of the lever to normal, so as to restore the absolute permissive block system to its normal mode of operation as soon as the train passes the first intermediate signal in advance of the hand throw switch by which it entered the block. For the sake of uniformity in manipulation, a similar three-position lever ESL is used for controlling switch @W, although a two-position lever could be used in this instance.

Referring now to Fig. 20, it will be seen that when a train enters the track section 4RT containing the hand throw switch 4W, the dropping of the track relay lRTR for that section completes a local circuit at its back contacts a and b to initiate the operation of a time element relay TER. The line circuits for controlling the entering signals 4RA and ZLA for the double track block include front contacts a, b, c and d of a repeating relay ATE-P which is normally energized over a :back contact a of relay 4TER and the circuit for relay tRI-ID also includes back contacts b and c of relay tTER. This arrangement serves to check the operation of relay dTER, that is to say, to insure that relay l'IER starts its operation from its normal position to measure a predetermined time before closing its front contacts band 0, relay iTER functioning like relay ZTER to prevent the unlocking of the switch in advance of an approaching high speed train. The crew of a train which consumes this time in section 4RT and stops at switch 4W may unlock the switch by removing its padlock 50 and opening contact 49 to release relay AWLP', therebyenergizing the lock magnet 4WL over'the circuit extending from terminal B at front contact 0 of relay iTEI-t, back contact at of relay 4WLSR, line wire 39, back contact d of relay 4WLP, magnet AWL, contacts 4B- il, back contact 0 of relay AWLP, line wire 33, back contact 0 of relay 4WLSR and front contact I) of relay dTER, to terminal C. Signals ERA and ZL'A are held at stop, their line circuits being held open by relay iRTR until the train clears the main line, and by relay lWLP until switch 4W is again locked normal.

To enable a train to enter the main line Via switch 4W, the central ofiice operator will move lever ASL to the left or right, the momentary closing of the lever contact or causing the delivery of a control code to the station of Fig. 20 in which channel 4 is energized over contact 0 of lever 4531, and contact 7c of relay 038 to reverse relay QWLS. If the block is vacant and signal 2LA is at stop with relay 2LAS energized or switch IW reversed, relay ARHD will be energized, and if signal ARA is also at stop with relay RAS energized or switch 3 reversed, a circuit will be completed from terminal B at the reverse contact a of relay 4WLS over front contact a of relay 4RHD and over front contacts g of relays lRAS and SIP or over contact h of relay 3RWP through relay GWLSR to terminal 0. Relay 4WLSR therefore picks up if conditions are proper for unlocking the switch, and is held energized over a stick cirl9 cuit including its own front contact a and the reverse contact a of relay EWLS. Contacts 0, cl, e and f of relay lWLSR open the line circuits for relays lRI-ID and ZLI-ID, and terminal B of the source at the station of Fig. 2C which is connected over back contact I) of relay lLAPC to contact I of relay GWLSR, becomes connected through resistor 20 and front contact (I of relay AWLSR to line wire 43 and thence over back contact b of relay ERAPC through relay ZRAR to terminal B of the source at the station of Fig. 2A, While terminals C of these two sources are connected together over back contacts a of relays ,QLAPC and ZRAPC, front contacts and e of relay GWLSR and line wire 42. Relay ZRAR consequently releases, releasing relay ZLBP to initiate an indication code for energizing relay ZLBK and thereby lighting lamp ZLBE in the track diagram.

When relay lWLSR is picked up, the release of relay @WLP by the train crew permits magnet lWL to be energized to unlock the switch over the circuit extending from terminal B at front contact a of relay GRTR, back contact I) of relay GLAPC and thence over front contacts f and d of relay lWL-SR and resistor 20, line wire 39, back contact d of relay lWLP, magnet tWL, contacts itll, contact 0 of relay lWLP, line wire 38, front contacts 0 and c of relay iW'LSR and thence to terminal C at front contact I) of relay lRTR.

After the unlock has been obtained, the operator will restore lever tSL to its normal center position thereby initiating a control code for restoring relay lWLS to normal to release relay lWLSR, the system becoming restored to its normal condition when switch 4W is locked normal with relay SWLP energized. It will be evident that other hand throw switches equipped like switch 4W may be located in any of the sections of the block extending from signal ERA to signal ZLA and that only one lever 4SL is required for their control.

Although I have herein shown and described only one form of railway trailic controlling apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination with a stretch of single track railway divided into block sections, signals gor governing trafiic movements in opposite directions into the stretch, a system of reversible circuits for controlling the signals; a line relay, an approach relay, a block relay and a trafiic direction relay at each end of the stretch; means controlled by the trafiic direction relays in corresponding position for revisibly connecting a source of current to said system of circuits at one end in series with the associated approach relay and .for connecting the line relay at the other end thereto to energize said approach relay when the adjacent block section is unoccupied and to distinctively energize said line relay only when the remaining block sections are unoccupied, means controlled by each line relay When distinctively energized for clearing the adjacent signal, and means for energizing each block relay when the adjacent approach relay is energized and also when the adjacent line relay is distinctively energized, and indication means controlled jointly by said block relays to indicate when the entire stretch is unoccupied.

2. In combination with a stretch of single track railway divided into block sections, signals for governing traffic movements in opposite directions into the stretch, a system of reversible circuits for controlling the signals; a line relay, an approach relay, a block relay and a traffic direction relay, at each end of the stretch; a master directional relay at a distant control ofiice, means for operating both traffic direction relays to positions corresponding to that of said master directional relay, means controlled by the traffic direction relays in corresponding positions for reversibly connecting a source of current to said system of circuits atone end in series with the associated approach relay and for connecting the line relay at the other end thereto to energize said approach relay when the adjacent block section is unoccupied and to distinctively energize said line relay only when the remaining block sections are unoccupied, means controlled by each line relay when distinctively energized for clearing the adjacent signal, means for energizing each block relay when the adjacent approach relay is energized and also when the adjacent line relay is distinctively energized, and means preventing the operation of said master directional relay from one position to another except when both of said block relays are energized.

3. In combination with a stretch of single track railway divided into block sections, signals for governing trafiic movements in opposite directions into the stretch, a system of reversible circuits for controlling the signals; a line relay, an approach relay, a block relay and a tralilc direction relay at each end of the stretch; a master directional relay at a distant control omce, means for operating both trafiic direction relays to positions corresponding with that of said master directional relay, means controlled by the trafiic direction relays in corresponding positions for reversibly connecting a source of current to said system of circuits at one end in series with the associated approach relay and for connecting the line relay at the other end thereto to simultaneously energize the approach relay at one end and the line relay at the other end of the stretch when the two block sections at opposite ends of the stretch are unoccupied, means efiective when the portion of the block between said end sections is unoccupied for supplying current of a distinctive character to said line relay, means controlled by each line relay for controlling the adjacent signal, means for energizing each block relay when the adjacent approach relay is energized and also when the adjacent line relay is energized by current of said distinctive character, indication relays at said ofiice for repeating the condition of said block relays, and means controlled by said indication relays for controlling said master directional relay.

4. In combination with a stretch of railway track having a signal at each end for governing the movement of traific into the stretch, a line relay, a traffic direction relay and a signal control relay at each end. of the stretch; a signal lever for each signal, two stick relays, a directional relay, and block indication means all located at a control omce; circuilts controlled by said traffic direction relays in one position for energizing the line relay at one end of the stretch, circuits controlled by said traffic direction relays in another position for energizing th line relay at the other end of the stretch, means governed by traflic conditions in said stretch for controlling said block indication means to indicate when the stretch is unoccupied, pick-up and stick circuits for one stick relay closed by the directional relay in one position and for the other stick relay closed by the directional relay in its other position, said pick-up circuits including contacts closed only when the block indication means indicates that the stretch is unoccupied, means for locally actuating said block indication means to open said contacts whereby one stick relay is released when the position of the directional relay is changed and the other does not become energized until the block indication means is again governed by traffic conditions to indicate that the stretch is unoccupied, a circuit controlled by each signal lever when reversed for operating the corresponding signal control relay, a circuit controlled by each signal lever effective if one signal lever or the other is reversed either when said block indicationmeans indicates that the stretch is unoccupied or when both stick relays are released to actuate said directional relay to a position corresponding to the desired direction of traflic movement through the stretch, means controlled by said directional relay for operating both traflic direction relays to positions in which the circuits they control are conditioned to effect the energization of that line relay which is associated with the operated signal con trol relay, and means controlled by such line relay and signal control relay for clearing the adjacent signal,

5. In combination with a stretch of railway track having a signal at each end for governing the movement of traffic into the stretch, a traffic direction relay at each end of the stretch, a signal control relay for each signal, circuits for said signals controlled jointly by both traffic direction relays for controlling the direction of traific movements into the stretch to permit the clearing of either signallin response to the operation of its signal control relay; a signal lever for each signal, a directional relay, signal indication means controlled by the signals and block indication means controlled by trafiic conditions in said stretch all located at a control office, circuits for operating said directional relay to one position when one signal lever is reversed and to another position when the other signal lever is reversed, effective only when the signal indication means indicates that the signals are at stop, and initially effective only when the block indication means indicates that the stretch is unoccupied, circuits controlled bysaid directional relay for operatingtboth traffic direction relays to positions in which the circuits they control are conditioned to set up the desired direction for traffic movements, means for maintaining the circuits for said directional relay effective after its position has been changed, regardless of the condition of said block indication means, said maintaining means being effective only until the block indication means is again operated in accordance with traffic conditions to indicate that the stretch is unoccupied, and a circuit controlled by each signal lever when reversed and by the directional relay in a corresponding position for energizing the associated signal control relay.

6. Railway traffic controlling apparatus comprising a signal at eachlend of a stretch of single track railway for governing the movement of traffic into the stretch, a group of code controlled relays including a traffic direction relay and a signal control relay at each end of the stretch, a system of reversible signal circuits controlled jointly by the traffic direction relays in corresponding positions which reflect the condition of occupancy of said stretch to render one signal. or the other responsive to the operation of its control relay, code controlled indication means at a control oflice for indicating the condition of said circuit system and of said signals, a signal lever for each signal, and a directional relay at said ofiice, circuits for operating the directional relay to one position or another in response to the reversal of one signal lever or th other effective when the indication means indicates that the stretch is unoccupied, provided neither signal has been cleared, a starting button for each signal lever, a code transmitter adapted to initiate the transmission of a code to one end of the stretch or the other in response'to the operation of one button or' the other, each such code including elements controlled by the signal lever associated with the operated button for operating the control relay for the signal which such lever controls to a position corresponding with that of its lever and for operating the traffic direction relay associated therewith to a position corresponding with that of the directional relay, direction locking means effective when released to render the operation of either button effective to initiate the transmission of such codes to both ends of the stretch, means for releasing said locking means in response to a change in the position of the directional relay, and means for maintaining said locking means released until new indications are received to indicate the reversal of said signal circuit system by said traffic direction relays in response to such codes.

'7. Railway traffic controlling apparatus comprising a signal at each end of a stretch of single track railway, a code controlled traffic direction relay at each end of the stretch for governing the direction of traffic movements through the stretch; a signal lever for each signal, a directional relay operable to one position by one signal lever and to another position by the other signal lever for selecting the desired direction of traffic movements through the stretch, block in- V dication means which indicates when the traflic direction indicated by said directional relay is established and a code transmitter, all located at a control office; a starting button for each signal lever, means responsive to the operation of each button to initiate thedelivery of a code by said transmitter to the corresponding end of the stretch for controlling the signal at that end inaccordance with the position of its lever and for also controlling the associated traffic direction relay in accordance with the position of such directional relay, and means responsive to a change in the position of said directional relay for rendering each starting button temporarily effective to initiate the transmission of such codes to both ends of the stretch, said last named means remaining efiective only until said block indication means is actuated to indicate that the traffic direction. has been reversed in response to the operation of the traffic direction relays by such codes.

8. Railway traffic controlling apparatus comprising a signal at each end of a stretch of single track railway-two code controlled traffic direction relays, one at each end of the stretch, for governing the direction of traffic movements through the stretch; a signal lever for each signal, direction selecting means controllable by said levers, for governing the operation of said trafiic direction relays and a code transmitter, all located at a control ofl'ice; a starting button for each signal lever, starting means responsive to the operation of each button for initiating the delivery of a code by said transmitter to the corresponding end of the stretch for controlling the signal at that end in accordance with the position of its lever and for also controlling the associated traffic direction relay in accordance with the condition of said direction selecting means, and means governed by said direction selecting means and acting only when the direction selected thereby is changed to render the starting means controlled by each button temporarily responsive to the operation of the other button, whereby the operation of either button to initiate the transmission of a code to one end of the stretch is automatically effective if such button is operated when the stretch is unoccupied and the desired trafiic direction is not set up to initiate the delivery of a, second code by said transmitter for controlling the trafllc direction relay at the other end of the stretch.

9. Railway traffic controlling apparatus comprising a signal at each end of a stretch of single track railway, a code controlled traffic direction relay at each end of the stretch a system of circuits controlled by said traffic direction relays for controlling the signals in accordance with traific conditions in the stretch and for controlling the direction of traffic movements through the stretch; a signal lever for each signal and a code transmitter located at a control ofiice; a starting button for each signal lever, starting means responsive to the operation ofeach button occurring when the associated signal lever is reversed and the required trafiic direction is already set up for initiating the delivery of a code by said transmitter to the corresponding end of the stretch, each such code including elements for controlling the signal and traffic direction relay at that end, and means acting automatically if the lever for either signal is reversed when the opposing traific direction is set up but the stretch is unoccupied and the opposing signal is at stop for initiating the delivery of codes by said transmitter to both ends of the stretch in response to a single operation of the starting button associated with such lever, said codes serving to position the traflic direction relays as required to reverse the trafficdirection and to clear the signal governed by the reversed signal lever.

10. In combination with a section of railway track including a hand throw switch, an electric lock for preventing the hand operation of the switch, a track relay for said section, an indication relay adjacent the switch having an energizing circuit closed only when the switch is locked in its normal position, a signal for governing the movement of traffic into said section, a time element relay adjacent the signal, an energizing circuit for the signal including line wires extending from the signal location to the location of the switch and including contacts controlled by the time element relay and closed in its normal position, and also including front contacts of said track relay and of said indication relay, means responsive to the release of said track relay for initiating the operation of said time element relay whenever a train enters said track section, means adjacent the switch for manually releasing said indication relay, and a circuit for energizing said electric lock to unlock the switch including back contacts of said indication relay, said line wires and contacts closed by the time element relay a predetermined time after its operation is initiated.

11. In combination witha section of railwal track including a hand throw switch, an electric lock for preventing the hand operation of the switch, an indication relay adjacent the switch having an energizing circuit closed only when the switch is locked in its normal position, a signal for governing trafiic movements into said section, a line circuit for controlling the signal including contacts closed only when the section is unoccupied and said indication relay is energized, a switch control relay adjacent the signal, a stick relay, a pick-up circuit for said stick relay including a contact of said control relay, a contact which when closed indicates that the signal is at stop, and a contact closed only when the line circuit for said signal is energized, a stick circuit for said stick relay including its own front contact and said control relay contact, and a circuit for energizing said electric lock to unlock the switch including back contacts of said indication relay and front contacts of said stick relay.

12. In combination with a stretch of single track railway having signals for governing trafiic movements in both directions through the stretch, a hand throw switch located in said stretch, an electric lock for preventin the hand operation of the switch, a reversible line circuit system for controlling said signals, a directional relay at a control ofiice for controlling the direction of energization of said line circuit system to govern the direction of traific movements through the stretch, a three-position switch lever having a normal position and two reverse positions corresponding to the two directions of traffic movement through the stretch, means responsive to the movement of said lever to either reverse position to prepare a circuit for energizing the electric lock to permit the unlocking of the switch and for also operating the directional relay to a position corresponding with that of said lever, and means rendered effective upon the restoration of said lever to its normal position for conditioning said line circuit system for train movements in direction corresponding to the operated position of said directional relay.

13. In combination with a stretch of single track railway, a hand throw track switch located in saidstretch, anelectric lock for preventing the hand operation of the switch, an indication relay adjacent the switch having an energizing circuit closed only when the switch is locked in its normal position, signals for governing trafiic movements in both directions through the stretch, a reversible line circuit system for controlling said signals and extending the length of the stretch,

I the portion adjacent said switch including front contacts of said indication relay, a directional relay at a control office for controlling the direction of energization of said line circuit system to thereby govern the direction of trafiic move ments through the stretch, a three-position switch control lever having a normal center position and two reverse positions corresponding to the two directions of trafiic movements through the stretch, means responsive to the movement of said lever to either reverse position for operating the directional relay to a corresponding position and for completing circuits including said line circuit system and back contacts of said indication relay to permit the energization of said electric lock to unlock the switch, and means rendered effective upon the restoration of said lever to its normal position with said indication relay again energized for conditioning said line circuit system for train movements in a direction corre- 25 sponding to the operated position of said directional relay.

HENRY S. YOUNG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Vanhorn Aug. 24, 1937 Number Name Date Wenholz Oct. 26, 1937 Allen Dec, 21, 1937 Phinney Feb. 22, 1938 Stoker Apr. 18, 1939 Pelikan June 1, 1943 Young Aug. 17, 1943 Mackey Oct. 8, 1940 Pelikan May 13, 1941 Van Horn Aug. 29, 1944 Van Horn "Mar. 14, 1944 

